Page 396 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

374 Major Process Equipment Maintenance and Repair

Packlng Case Disassembly, Larger TClrbines

The steam end and exhaust end packing cases (1 1. Figure 8-5) furnished
on larger turbines, extend beneath the turbine casing cover. This design
(shown in Figure 8-7) requires that the casing cover be removed before
removing the top half packing cases.

1. Remove cap screws (7, Figure 8-5) from the vertical flanges on the top
halves of the packing cases and remove turbine casing cover as out-
lined in Disassembly Section.
2. Remove cap screws (8) from horizontal packing case flange and
break the horizontal joint by prying the top halves of packing cases
away from the bottom halves.
3. Carellly remove the top halves of the packing cases by lifting
straight up until they clear the carbon ring assemblies.

Carbon Rlng Replacement

1. Unhook the retahing spring surrounding the carbon ring.
2. Remove the anti-rotation stop by sliding it off the retaining spring.
3. Remove the carbon ring segments by rotating them around the rotor
shaft.
4. Pull the retaining spring from the packing case.
Note: Do not mix carbon ring segments. Mark each ring so it can
be returned to its original location.

5. Clean the packing cases, rotor shaft and all sealing surfaces on the
packing case flanges. Blow out the packing cases with high pres-
sure air.
6. Place the carbon ring retaining springs under and part way around
the rotor shaft.
7. Roll the carbon ring segments around the shaft and into the packing
case grooves. Align the match marks on the carbon ring segments
to assure proper assembly.
8. Slide the anti-rotation stops onto the retainer springs and position
the stops in notched carbon ring segments.
9. Hook the ends of each retaining spring together and rotate the car-
bon rings so the anti-rotation stops are seated in the anti-rotation
notches in the bottom half packing cases.